There is an increasing need for multi-circuit packages for use with electronic assemblies and in the computer industry. As both complexity and miniaturization increases, the need for smaller size, lighter weight packaging and reliability has generated the need for connectors having the ability to reliably connect a large number of electrically conductive traces on closely spaced centerlines in compact areas. Furthermore, there are a number of electronic devices that utilize liquid crystal display units, and circuitry on glass panels and the like that cannot be electrically connected by means of individually soldered connections. The requirements of the industry have generated a class of connectors known as elastomeric connectors which can be disposed between circuitry on for example a printed circuit board and also on a glass panel to interconnect corresponding circuits while avoiding the use of solder. The elastomeric member provides sufficient normal force to maintain the electrical interconnection of the circuits yet the member has sufficient compliancy so as not to damage the glass or other panels.
U.S. Pat. No. 4,820,170 discloses one such layered elastomeric connector in which succeeding layers of dielectric material and conductive material are alternated so as to provide a plurality of closely spaced but electrically isolated conductive areas. Typically the elastomeric connector is a rectangular block such that each layer is exposed on all four sides of the block, thus enabling interconnection between circuits on parallel planes or between circuits on planes that meet at essentially right angles. Since the elastomeric connector is compressible and will expand outwardly when subjected to pressure, means must be provided to support the elastomeric block in order to control the direction of expansion and maintain the block in appropriate alignment and to provide dimensioned stability for the block. In using such an elastomeric connector, therefore, a separate support housing or a special cavity within a connector housing is required. These additional parts for providing interconnection add to the number of pieces that must be molded or otherwise formed in order to achieve and maintain the desired interconnection.
Instrument panels for automobiles, airplanes, computers and other equipment often include electronic packages such as digital clocks and the like which require interconnection to fragile surfaces such as glass panels having conductors thereon for example liquid crystal display units (LCDs). Typically such panel mounted electronic assemblies contain at least one printed circuit board having a variety of electronic components thereon, a housing for the components, electrical connectors interconnecting these components and at least one elastomeric connector to join the circuitry to an LCD or the like.
It is desirable, therefore, to provide a means for making electronic assemblies such as panel mounted assemblies with a minimum number of parts.
It is further desirable to minimize the steps in manufacturing such an assembly.
It is also desirable to have an assembly that is relatively lightweight and compact while maintaining the desired electronic capabilities of the more complex prior art devices.
The use of compliant spring arm contact members for providing surface mounting for components to surfaces such as circuit boards is known. These compliant spring arm member, however, are typically made of metal that has been stamped and formed into the desired configuration. While suitable for many applications, metal spring arms are not typically suitable for surface interconnection to fine line circuitry on panels such as glass panels and the like. Furthermore the stamping and forming of metal requires further manufacturing steps.
It is desirable, therefore, to have a compliant spring arm section formed essentially of dielectric material, which will eliminate the problems of possible damage to the surface of the glass as well as have a sufficient compression force to maintain electrical contact with the surface conductors.
Furthermore, it is desirable to maintain the features of spring contacts while eliminating stamping and forming steps required for metal members thus providing a cost effective method for manufacturing.